content/browser/renderer_host/input/gesture_event_queue.cc

   1 // Copyright 2014 The Chromium Authors. All rights reserved.
   2 // Use of this source code is governed by a BSD-style license that can be
   3 // found in the LICENSE file.
   4
   5 #include "content/browser/renderer_host/input/gesture_event_queue.h"
   6
   7 #include "base/trace_event/trace_event.h"
   8 #include "content/browser/renderer_host/input/touchpad_tap_suppression_controller.h"
   9 #include "content/browser/renderer_host/input/touchscreen_tap_suppression_controller.h"
  10
  11 using blink::WebGestureEvent;
  12 using blink::WebInputEvent;
  13
  14 namespace content {
  15 namespace {
  16
  17 // Whether |event_in_queue| is GesturePinchUpdate or GestureScrollUpdate and
  18 // has the same modifiers/source as the new scroll/pinch event. Compatible
  19 // scroll and pinch event pairs can be logically coalesced.
  20 bool IsCompatibleScrollorPinch(
  21     const GestureEventWithLatencyInfo& new_event,
  22     const GestureEventWithLatencyInfo& event_in_queue) {
  23   DCHECK(new_event.event.type == WebInputEvent::GestureScrollUpdate ||
  24          new_event.event.type == WebInputEvent::GesturePinchUpdate)
  25       << "Invalid event type for pinch/scroll coalescing: "
  26       << WebInputEventTraits::GetName(new_event.event.type);
  27   DLOG_IF(WARNING, new_event.event.timeStampSeconds <
  28                        event_in_queue.event.timeStampSeconds)
  29       << "Event time not monotonic?\n";
  30   return (event_in_queue.event.type == WebInputEvent::GestureScrollUpdate ||
  31           event_in_queue.event.type == WebInputEvent::GesturePinchUpdate) &&
  32          event_in_queue.event.modifiers == new_event.event.modifiers &&
  33          event_in_queue.event.sourceDevice == new_event.event.sourceDevice;
  34 }
  35
  36 // Returns the transform matrix corresponding to the gesture event.
  37 gfx::Transform GetTransformForEvent(
  38     const GestureEventWithLatencyInfo& gesture_event) {
  39   gfx::Transform gesture_transform;
  40   if (gesture_event.event.type == WebInputEvent::GestureScrollUpdate) {
  41     gesture_transform.Translate(gesture_event.event.data.scrollUpdate.deltaX,
  42                                 gesture_event.event.data.scrollUpdate.deltaY);
  43   } else if (gesture_event.event.type == WebInputEvent::GesturePinchUpdate) {
  44     float scale = gesture_event.event.data.pinchUpdate.scale;
  45     gesture_transform.Translate(-gesture_event.event.x, -gesture_event.event.y);
  46     gesture_transform.Scale(scale, scale);
  47     gesture_transform.Translate(gesture_event.event.x, gesture_event.event.y);
  48   } else {
  49     NOTREACHED() << "Invalid event type for transform retrieval: "
  50                  << WebInputEventTraits::GetName(gesture_event.event.type);
  51   }
  52   return gesture_transform;
  53 }
  54
  55 }  // namespace
  56
  57 GestureEventQueue::Config::Config() : enable_fling_cancel_filtering(true) {
  58 }
  59
  60 GestureEventQueue::GestureEventQueue(
  61     GestureEventQueueClient* client,
  62     TouchpadTapSuppressionControllerClient* touchpad_client,
  63     const Config& config)
  64     : client_(client),
  65       enable_fling_cancel_filtering_(config.enable_fling_cancel_filtering),
  66       active_fling_count_(0),
  67       scrolling_in_progress_(false),
  68       ignore_next_ack_(false),
  69       touchpad_tap_suppression_controller_(
  70           touchpad_client,
  71           config.touchpad_tap_suppression_config),
  72       touchscreen_tap_suppression_controller_(
  73           this,
  74           config.touchscreen_tap_suppression_config),
  75       debounce_interval_(config.debounce_interval) {
  76   DCHECK(client);
  77   DCHECK(touchpad_client);
  78 }
  79
  80 GestureEventQueue::~GestureEventQueue() { }
  81
  82 void GestureEventQueue::QueueEvent(
  83     const GestureEventWithLatencyInfo& gesture_event) {
  84   TRACE_EVENT0("input", "GestureEventQueue::QueueEvent");
  85   if (!ShouldForwardForBounceReduction(gesture_event) ||
  86       !ShouldForwardForGFCFiltering(gesture_event) ||
  87       !ShouldForwardForTapSuppression(gesture_event)) {
  88     return;
  89   }
  90
  91   QueueAndForwardIfNecessary(gesture_event);
  92 }
  93
  94 bool GestureEventQueue::ShouldDiscardFlingCancelEvent(
  95     const GestureEventWithLatencyInfo& gesture_event) const {
  96   if (!enable_fling_cancel_filtering_)
  97     return false;
  98
  99   GestureQueue::const_reverse_iterator it =
 100       coalesced_gesture_events_.rbegin();
 101   while (it != coalesced_gesture_events_.rend()) {
 102     if (it->event.type == WebInputEvent::GestureFlingStart)
 103       return false;
 104     if (it->event.type == WebInputEvent::GestureFlingCancel)
 105       return true;
 106     it++;
 107   }
 108   // If there are no fling-affecting events in the queue, and there's still an
 109   // active fling in the renderer, the cancel event should not be dropped.
 110   return !active_fling_count_;
 111 }
 112
 113 bool GestureEventQueue::ShouldForwardForBounceReduction(
 114     const GestureEventWithLatencyInfo& gesture_event) {
 115   if (debounce_interval_ <= base::TimeDelta())
 116     return true;
 117   switch (gesture_event.event.type) {
 118     case WebInputEvent::GestureScrollUpdate:
 119       if (!scrolling_in_progress_) {
 120         debounce_deferring_timer_.Start(
 121             FROM_HERE,
 122             debounce_interval_,
 123             this,
 124             &GestureEventQueue::SendScrollEndingEventsNow);
 125       } else {
 126         // Extend the bounce interval.
 127         debounce_deferring_timer_.Reset();
 128       }
 129       scrolling_in_progress_ = true;
 130       debouncing_deferral_queue_.clear();
 131       return true;
 132     case WebInputEvent::GesturePinchBegin:
 133     case WebInputEvent::GesturePinchEnd:
 134     case WebInputEvent::GesturePinchUpdate:
 135       // TODO(rjkroege): Debounce pinch (http://crbug.com/147647)
 136       return true;
 137     default:
 138       if (scrolling_in_progress_) {
 139         debouncing_deferral_queue_.push_back(gesture_event);
 140         return false;
 141       }
 142       return true;
 143   }
 144 }
 145
 146 bool GestureEventQueue::ShouldForwardForGFCFiltering(
 147     const GestureEventWithLatencyInfo& gesture_event) const {
 148   return gesture_event.event.type != WebInputEvent::GestureFlingCancel ||
 149       !ShouldDiscardFlingCancelEvent(gesture_event);
 150 }
 151
 152 bool GestureEventQueue::ShouldForwardForTapSuppression(
 153     const GestureEventWithLatencyInfo& gesture_event) {
 154   switch (gesture_event.event.type) {
 155     case WebInputEvent::GestureFlingCancel:
 156       if (gesture_event.event.sourceDevice ==
 157           blink::WebGestureDeviceTouchscreen)
 158         touchscreen_tap_suppression_controller_.GestureFlingCancel();
 159       else
 160         touchpad_tap_suppression_controller_.GestureFlingCancel();
 161       return true;
 162     case WebInputEvent::GestureTapDown:
 163     case WebInputEvent::GestureShowPress:
 164     case WebInputEvent::GestureTapUnconfirmed:
 165     case WebInputEvent::GestureTapCancel:
 166     case WebInputEvent::GestureTap:
 167     case WebInputEvent::GestureDoubleTap:
 168       if (gesture_event.event.sourceDevice ==
 169           blink::WebGestureDeviceTouchscreen) {
 170         return !touchscreen_tap_suppression_controller_.FilterTapEvent(
 171             gesture_event);
 172       }
 173       return true;
 174     default:
 175       return true;
 176   }
 177 }
 178
 179 void GestureEventQueue::QueueAndForwardIfNecessary(
 180     const GestureEventWithLatencyInfo& gesture_event) {
 181   switch (gesture_event.event.type) {
 182     case WebInputEvent::GesturePinchUpdate:
 183     case WebInputEvent::GestureScrollUpdate:
 184       QueueScrollOrPinchAndForwardIfNecessary(gesture_event);
 185       return;
 186     default:
 187       break;
 188   }
 189
 190   coalesced_gesture_events_.push_back(gesture_event);
 191   if (coalesced_gesture_events_.size() == 1)
 192     client_->SendGestureEventImmediately(gesture_event);
 193 }
 194
 195 void GestureEventQueue::ProcessGestureAck(InputEventAckState ack_result,
 196                                           WebInputEvent::Type type,
 197                                           const ui::LatencyInfo& latency) {
 198   TRACE_EVENT0("input", "GestureEventQueue::ProcessGestureAck");
 199
 200   if (coalesced_gesture_events_.empty()) {
 201     DLOG(ERROR) << "Received unexpected ACK for event type " << type;
 202     return;
 203   }
 204
 205   if (ack_result == INPUT_EVENT_ACK_STATE_CONSUMED &&
 206       type == blink::WebInputEvent::GestureFlingStart) {
 207     ++active_fling_count_;
 208   }
 209
 210   // It's possible that the ack for the second event in an in-flight, coalesced
 211   // Gesture{Scroll,Pinch}Update pair is received prior to the first event ack.
 212   // TODO(jdduke): Unify GSU/GPU pairs into a single event, crbug.com/359115.
 213   size_t event_index = 0;
 214   if (ignore_next_ack_ &&
 215       coalesced_gesture_events_.size() > 1 &&
 216       coalesced_gesture_events_[0].event.type != type &&
 217       coalesced_gesture_events_[1].event.type == type) {
 218     event_index = 1;
 219   }
 220   GestureEventWithLatencyInfo event_with_latency =
 221       coalesced_gesture_events_[event_index];
 222   DCHECK_EQ(event_with_latency.event.type, type);
 223   event_with_latency.latency.AddNewLatencyFrom(latency);
 224
 225   // Ack'ing an event may enqueue additional gesture events.  By ack'ing the
 226   // event before the forwarding of queued events below, such additional events
 227   // can be coalesced with existing queued events prior to dispatch.
 228   client_->OnGestureEventAck(event_with_latency, ack_result);
 229
 230   const bool processed = (INPUT_EVENT_ACK_STATE_CONSUMED == ack_result);
 231   if (type == WebInputEvent::GestureFlingCancel) {
 232     if (event_with_latency.event.sourceDevice ==
 233         blink::WebGestureDeviceTouchscreen)
 234       touchscreen_tap_suppression_controller_.GestureFlingCancelAck(processed);
 235     else
 236       touchpad_tap_suppression_controller_.GestureFlingCancelAck(processed);
 237   }
 238   DCHECK_LT(event_index, coalesced_gesture_events_.size());
 239   coalesced_gesture_events_.erase(coalesced_gesture_events_.begin() +
 240                                   event_index);
 241
 242   if (ignore_next_ack_) {
 243     ignore_next_ack_ = false;
 244     return;
 245   }
 246
 247   if (coalesced_gesture_events_.empty())
 248     return;
 249
 250   const GestureEventWithLatencyInfo& first_gesture_event =
 251       coalesced_gesture_events_.front();
 252
 253   // TODO(jdduke): Unify GSU/GPU pairs into a single event, crbug.com/359115.
 254   // Check for the coupled GesturePinchUpdate before sending either event,
 255   // handling the case where the first GestureScrollUpdate ack is synchronous.
 256   GestureEventWithLatencyInfo second_gesture_event;
 257   if (first_gesture_event.event.type == WebInputEvent::GestureScrollUpdate &&
 258       coalesced_gesture_events_.size() > 1 &&
 259       coalesced_gesture_events_[1].event.type ==
 260           WebInputEvent::GesturePinchUpdate) {
 261     second_gesture_event = coalesced_gesture_events_[1];
 262     ignore_next_ack_ = true;
 263   }
 264
 265   client_->SendGestureEventImmediately(first_gesture_event);
 266   if (second_gesture_event.event.type != WebInputEvent::Undefined)
 267     client_->SendGestureEventImmediately(second_gesture_event);
 268 }
 269
 270 TouchpadTapSuppressionController*
 271     GestureEventQueue::GetTouchpadTapSuppressionController() {
 272   return &touchpad_tap_suppression_controller_;
 273 }
 274
 275 void GestureEventQueue::DidStopFlinging() {
 276   DCHECK_GE(active_fling_count_, 0);
 277   --active_fling_count_;
 278 }
 279
 280 void GestureEventQueue::ForwardGestureEvent(
 281     const GestureEventWithLatencyInfo& gesture_event) {
 282   QueueAndForwardIfNecessary(gesture_event);
 283 }
 284
 285 void GestureEventQueue::SendScrollEndingEventsNow() {
 286   scrolling_in_progress_ = false;
 287   if (debouncing_deferral_queue_.empty())
 288     return;
 289   GestureQueue debouncing_deferral_queue;
 290   debouncing_deferral_queue.swap(debouncing_deferral_queue_);
 291   for (GestureQueue::const_iterator it = debouncing_deferral_queue.begin();
 292        it != debouncing_deferral_queue.end(); it++) {
 293     if (ShouldForwardForGFCFiltering(*it) &&
 294         ShouldForwardForTapSuppression(*it)) {
 295       QueueAndForwardIfNecessary(*it);
 296     }
 297   }
 298 }
 299
 300 void GestureEventQueue::QueueScrollOrPinchAndForwardIfNecessary(
 301     const GestureEventWithLatencyInfo& gesture_event) {
 302   DCHECK_GE(coalesced_gesture_events_.size(), EventsInFlightCount());
 303   const size_t unsent_events_count =
 304       coalesced_gesture_events_.size() - EventsInFlightCount();
 305   if (!unsent_events_count) {
 306     coalesced_gesture_events_.push_back(gesture_event);
 307     if (coalesced_gesture_events_.size() == 1) {
 308       client_->SendGestureEventImmediately(gesture_event);
 309     } else if (coalesced_gesture_events_.size() == 2) {
 310       DCHECK(!ignore_next_ack_);
 311       // If there is an in-flight scroll, the new pinch can be forwarded
 312       // immediately, avoiding a potential frame delay between the two
 313       // (similarly for an in-flight pinch with a new scroll).
 314       const GestureEventWithLatencyInfo& first_event =
 315           coalesced_gesture_events_.front();
 316       if (gesture_event.event.type != first_event.event.type &&
 317           IsCompatibleScrollorPinch(gesture_event, first_event)) {
 318         ignore_next_ack_ = true;
 319         client_->SendGestureEventImmediately(gesture_event);
 320       }
 321     }
 322     return;
 323   }
 324
 325   GestureEventWithLatencyInfo* last_event = &coalesced_gesture_events_.back();
 326   if (last_event->CanCoalesceWith(gesture_event)) {
 327     last_event->CoalesceWith(gesture_event);
 328     return;
 329   }
 330
 331   if (!IsCompatibleScrollorPinch(gesture_event, *last_event)) {
 332     coalesced_gesture_events_.push_back(gesture_event);
 333     return;
 334   }
 335
 336   GestureEventWithLatencyInfo scroll_event;
 337   GestureEventWithLatencyInfo pinch_event;
 338   scroll_event.event.modifiers |= gesture_event.event.modifiers;
 339   scroll_event.event.sourceDevice = gesture_event.event.sourceDevice;
 340   scroll_event.event.timeStampSeconds = gesture_event.event.timeStampSeconds;
 341   // Keep the oldest LatencyInfo.
 342   DCHECK_LE(last_event->latency.trace_id, gesture_event.latency.trace_id);
 343   scroll_event.latency = last_event->latency;
 344   pinch_event = scroll_event;
 345   scroll_event.event.type = WebInputEvent::GestureScrollUpdate;
 346   pinch_event.event.type = WebInputEvent::GesturePinchUpdate;
 347   pinch_event.event.x = gesture_event.event.type ==
 348       WebInputEvent::GesturePinchUpdate ?
 349           gesture_event.event.x : last_event->event.x;
 350   pinch_event.event.y = gesture_event.event.type ==
 351       WebInputEvent::GesturePinchUpdate ?
 352           gesture_event.event.y : last_event->event.y;
 353
 354   gfx::Transform combined_scroll_pinch = GetTransformForEvent(*last_event);
 355   // Only include the second-to-last event in the coalesced pair if it exists
 356   // and can be combined with the new event.
 357   if (unsent_events_count > 1) {
 358     const GestureEventWithLatencyInfo& second_last_event =
 359         coalesced_gesture_events_[coalesced_gesture_events_.size() - 2];
 360     if (IsCompatibleScrollorPinch(gesture_event, second_last_event)) {
 361       // Keep the oldest LatencyInfo.
 362       DCHECK_LE(second_last_event.latency.trace_id,
 363                 scroll_event.latency.trace_id);
 364       scroll_event.latency = second_last_event.latency;
 365       pinch_event.latency = second_last_event.latency;
 366       combined_scroll_pinch.PreconcatTransform(
 367           GetTransformForEvent(second_last_event));
 368       coalesced_gesture_events_.pop_back();
 369     }
 370   }
 371   combined_scroll_pinch.ConcatTransform(GetTransformForEvent(gesture_event));
 372   coalesced_gesture_events_.pop_back();
 373
 374   float combined_scale =
 375       SkMScalarToFloat(combined_scroll_pinch.matrix().get(0, 0));
 376   float combined_scroll_pinch_x =
 377       SkMScalarToFloat(combined_scroll_pinch.matrix().get(0, 3));
 378   float combined_scroll_pinch_y =
 379       SkMScalarToFloat(combined_scroll_pinch.matrix().get(1, 3));
 380   scroll_event.event.data.scrollUpdate.deltaX =
 381       (combined_scroll_pinch_x + pinch_event.event.x) / combined_scale -
 382       pinch_event.event.x;
 383   scroll_event.event.data.scrollUpdate.deltaY =
 384       (combined_scroll_pinch_y + pinch_event.event.y) / combined_scale -
 385       pinch_event.event.y;
 386   coalesced_gesture_events_.push_back(scroll_event);
 387   pinch_event.event.data.pinchUpdate.scale = combined_scale;
 388   coalesced_gesture_events_.push_back(pinch_event);
 389 }
 390
 391 size_t GestureEventQueue::EventsInFlightCount() const {
 392   if (coalesced_gesture_events_.empty())
 393     return 0;
 394
 395   if (!ignore_next_ack_)
 396     return 1;
 397
 398   DCHECK_GT(coalesced_gesture_events_.size(), 1U);
 399   return 2;
 400 }
 401
 402 }  // namespace content